1. Field of the Invention
The present invention is in the field of cryogenic cooler multistage regenerator-displacers wherein the various stages are not mechanically linked but move freely due to pressure waves at an input end of the cooler and wherein adjacent displacers telescope with each other.
2. Description of the Prior Art
There is a need in the latest cryogenic cooler systems to provide extremely cold temperatures for a longer period of time than is possible with the latest cooling systems. Problems have existed in previous coolers of excessive wear in the displacer seals caused by low temperature contraction or poor axial alignment and by having a limited frequency cycles of operation which limits the amount of total cooling at the cold end.